The present invention relates to devices for administering, injecting, delivering or dispensing a substance and to methods of making and using such devices. More particularly, it relates to ampoules or substance containers associated with such devices, and to a multi-chamber ampoule adapted to prevent leakage or an undesired escape or movement of a substance contained therein, e.g., a fluid product. More particularly, it relates to a multi-chamber ampoule with two pistons, wherein one of the pistons displays a material for sealing a bypass and/or can act as an absorptive seal.
Multi-chamber ampoules are known in the prior art. By such multi-chamber ampoules, e.g., two-chamber ampoules, fluid products consisting of several components are administered to a patient, which components are not mixed together until shortly before the administration. Generally, provided for this purpose are, in a first chamber, a fluid consisting of solvent and, in a second chamber, a product component in solid or fluid state. The solvent and the product component are mixed together in the ampoule by a mixing device and/or process. With the aid of the mixing device, the fluid product to be injected can be mixed shortly before an administration by an administration device through the displacement of a plug in such a manner that, via a supply channel, the solvent comes into contact with the product component and mixes together with the latter.
In some embodiments of two-chamber ampoules, the fluid product component is located between two pistons. For the mixing together, a force is exerted on a piston, which force is transferred to the other piston through the incompressibility of the fluid, so that both pistons and the product component are pushed in a discharge direction, until the piston pointing in the discharge direction has been completely displaced into a region of a bypass, which region is formed through the housing. Via the bypass, the fluid product component is now guided past the piston, so that this piston only moves again when the rear piston strikes the front piston. From now on, both pistons are moved in the discharge direction, so that the mixed product can be discharged.
However, the bypass in the housing still contains, with the discharge movement, fluid remnants of the fluid product component. If both pistons have passed the bypass, then remnants of the fluid product component run or leak out of the bypass, in a direction opposite to the discharge direction, and into a region behind the pistons. From this arises the problem that the mechanism provided for the mixing and discharging of the contents of the two- or multi-chamber ampoule becomes contaminated. For one thing, this is unhygienic, and, for another thing, the mechanism could become fouled or gummed up and no longer function in an normal manner.